JPH10293523A - Duplication method of relief image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and efficiency duplicate relief images without the need for executing the process for manufacturing hologram original plates for each relief image to be duplicated. SOLUTION: A photosetting thermoplastic resin compsn. layer 12 which is formed on a base 11 and is provided with rugged relief patterns 13 its surface is irradiated with light 16 of the irradiation quantity meeting the gradation of the desired image, by which the regions 12a, 12b, 12c varying in the degrees of photosetting in correspondence to the irradiation quantity thereof are formed. The regions 12a, 12b, 12c varying in the degrees o photosetting are thermally deformed in corresponding to the irradiation quantity by heating this layer and are irradiated with light 19, by which the thermally deformed patterns are fixed. The original plate 29 for duplicating the relief images is thereby manufactured. A duplication mold is manufactured from the original plate 20 and the relief images are duplicated a mateal to be formed with the images by using such original plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for duplicating a relief image, and more particularly to a method for duplicating a relief image suitable for producing a surface relief hologram.

[0002]

2. Description of the Related Art Holograms, which reproduce a three-dimensional three-dimensional image, are preferred for their excellent design, and are used for the covers of books, magazines, etc., POPs, gifts, decorations of packaging materials, and the like. Since holograms are equivalent to recording information on the order of submicrons, they are also used to prevent counterfeiting of securities, credit cards, and the like.

Conventionally, when producing a relief type hologram, a photoresist layer is provided on a glass plate by a method such as spin coating, and the surface of the photoresist layer is exposed to laser interference fringes, and then wet development processing such as alkali development is performed. Is performed to form a grating image (diffraction grating image) to produce a hologram master. In particular, when forming a grating image that is a binary image such as a character, a mask made of a silver halide dry plate or the like is further brought into close contact with the surface of the photoresist layer of the hologram master, and then exposed and developed. Has been done.

In order to perform replication from the hologram image master, a mold is formed from the surface of the photoresist layer of the hologram image master manufactured as described above using a technique such as metal plating, and the obtained mold is covered. 2. Description of the Related Art A method in which a relief is transferred to a material to be image-formed by applying pressure and heat to the image-forming material in close contact.

[0005]

As described above, in the conventional method for producing a relief-type hologram master,
Each image to be duplicated requires a series of time-consuming steps such as application of photoresist, exposure of laser interference fringes, and wet development, and complicated work. It is necessary to go through the process of preparing a hologram master starting from the application of a photoresist for each relief image to be obtained.

Accordingly, an object of the present invention is to provide a relief image duplicating method capable of duplicating a simpler and more efficient relief image without having to go through a process of preparing a hologram master for each relief image to be duplicated. It is in.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a photocurable thermoplastic resin composition which has a relief pattern on the surface of a support and which is in a solid state at room temperature. Forming a material layer, and irradiating the thermoplastic resin composition layer with light having an irradiation amount corresponding to the gradation of a desired image to form regions having different photocuring degrees corresponding to the irradiation amount of the light. Heating the thermoplastic resin composition layer on which the regions having different photocuring degrees are formed at a constant temperature, thereby thermally deforming the regions having different photocuring degrees in accordance with the photocuring degrees; Producing a relief image duplication master by fixing a heat deformation pattern by irradiating the thermoplastic resin composition layer with light, a step of producing a duplication mold from the relief image duplication original, and Relief It provides a method for duplicating a relief image, characterized in that it comprises the step of replicating the relief image to said image forming member by pressurizing under heating the image forming material on the image pattern surface. In the present invention, the irradiation of the light is usually
This is performed via a mask having regions having different light transmittances corresponding to the gradation of a desired image.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG.
Room temperature (15 ° C. to 35 ° C.), photocurable on support 11
To form a layer 12 of a thermoplastic resin composition in a solid state.

In the present invention, as the thermoplastic and photocurable resin composition which is in a solid state at room temperature, a photopolymerization initiator is added to a mixture of an ordinary thermoplastic resin and a crosslinkable compound having at least bifunctionality. What was blended can be used. Acrylic resin,
Styrene-acrylic copolymer resin, polyester resin, polyvinyl butyral resin, polycarbonate resin, vinyl chloride-vinyl acetate copolymer resin, styrene resin, vinyl chloride resin, acrylonitrile-styrene copolymer resin, thermoplastic polyurethane resin, etc. may be used. it can. Examples of the crosslinkable compound include various acrylates and methacrylates. As the photopolymerization initiator,
Self-cleavable compounds represented by derivatives such as benzoin, benzyl ketal and acetophenone, and various hydrogen abstraction type photopolymerization initiators having a molecular structure such as benzophenone, aromatic ketone and Michler's ketone can be used. These photopolymerization initiators can be used in combination with various photosensitizers.

If the crosslinkable compound itself is in a solid state at room temperature and exhibits thermoplasticity, it is not necessary to use a usual thermoplastic resin. Examples of such crosslinking compounds include various urethane acrylates and methacrylates, bisphenol A and bisphenol S in the molecule.
Epoxy acrylate and methacrylate, polybutadiene urethane methacrylate, polystyrene ethyl methacrylate, etc. having such a structure. In the present invention, an aqueous ultraviolet curable resin may be used.

[0011] Such a thermoplastic resin composition layer 12 comprises:
For example, it can be formed on the support 11 by a known coating method such as spin coating, knife coating, roll coating, and bar coating. When the thermoplastic resin layer is to be formed partially on the support, a general printing technique such as screen printing or gravure printing or a transfer technique can be used.

The support 11 is not particularly limited as long as it can sufficiently secure the adhesiveness to the thermoplastic resin composition. For example, it can be formed of an organic or inorganic material such as metal, paper, a polymer material, glass, and ceramic. The shape of the support 11 may be any of a plate, a sheet, and a film.

Next, as shown in FIG. 1B, an uneven relief pattern 13 is formed on the surface of the thermoplastic resin composition layer 12. More specifically, the relief surface of the relief pattern mold 14 is brought into close contact with the thermoplastic resin layer 12,
The relief pattern 13 is formed by heating and pressing. The relief pattern mold 14 is not particularly limited as long as it can apply (transfer) a relief pattern having preferably a uniform unevenness to the surface of the thermoplastic resin composition layer 12 by heating and pressing, but it is not particularly limited. When duplicating a mold hologram, a photoresist layer is formed on a glass plate according to a conventional method, and after exposing the photoresist layer to laser interference fringes, a grating pattern is formed by alkali development or the like. It can be manufactured by molding. It can also be manufactured by forming fine grooves in a diffraction grating pattern on a glass plate.

In the present invention, the phrase that the thermoplastic resin composition layer 12 is in a solid state at room temperature means that the relief pattern applied by heating and pressurization can be maintained at room temperature as described above. To a very solid state.

After forming an arbitrary relief pattern 13 on the surface of the thermoplastic resin composition layer 12 as described above,
The thermoplastic resin composition layer 12 is irradiated with an amount of light corresponding to a desired image gradation. More specifically, FIG.
As shown in (c), for example, a predetermined light is applied to a mask 15 composed of a portion 15a that transmits light 16 almost completely, a portion 15c that does not transmit light at all, and a portion 15b that transmits light approximately between these portions. (E.g., ultraviolet light). Thermoplastic resin composition layer 1 exposed through portion 15a of mask 15 that transmits light almost completely
2 are light cured to the highest extent and the mask 1
The region 12c of the thermoplastic resin composition layer 12 corresponding to the portion 15c that does not transmit the light 5 at all is hardly photocured. The region 12b of the thermoplastic resin composition layer 12 exposed through the portion 15b of the mask 15 is light-cured to an intermediate degree therebetween. Needless to say, the light used has a wavelength suitable for activating the photopolymerization initiator contained in the thermoplastic resin composition layer and performing photocuring, for example, ultraviolet light. The mask may be a negative or positive film obtained by photographing and developing a desired object.

Thus, a plurality of regions 12a, 12b and 12c having different degrees of curing are formed in the thermoplastic resin composition layer 12 in accordance with the amount of light irradiation (exposure).
These can be referred to as photocurable latent image areas.

Next, a plurality of photo-curable latent image areas 12a, 1a
Thermoplastic resin composition layer 1 on which 2b and 12c are formed
2 is heated at a constant temperature to form a photo-curable latent image area 1
2a, 12b and 12c are thermally deformed according to their degree of cure. Although the layer 12 has a different degree of cure, it is originally a thermoplastic material. Therefore, as shown in FIG. 1D, for example, heating conditions sufficient to flatten the relief pattern of the uncured region 12 c (see FIG. 1D). By performing the heat treatment at a temperature and time, the uneven relief pattern in the region 12c disappears, the surface 18 is flattened, and the region 1c having the highest degree of hardening is obtained.
2a loses thermoplasticity due to photocuring, hardly undergoes thermal deformation by this heat treatment, and the relief pattern 13 on the surface is maintained almost as it is. The region 12b having an intermediate degree of cure has a surface 17 that is thermally deformed to an intermediate degree between these. Thus, the latent image in the photocurable latent image area is visualized by this heat treatment, and becomes visible.

Thereafter, as shown in FIG. 1E, the thermoplastic resin composition layer 12 having a visualized heat-deformed region is formed.
The entire surface is exposed to light to fix the visualized image, thereby obtaining a relief image duplication master 20.

As is clear from the above description, the heating conditions (temperature and time) for performing the above-mentioned thermal deformation can be determined by the amount of light exposure. Therefore, the mixing ratio of the photocurable thermoplastic resin composition and the amount of exposure to irradiation light are determined according to the desired contrast ratio between the visualized images, and the heating conditions are set accordingly. This can be done by simple preliminary experiments.

Next, a copy mold is prepared by using the relief image copy master 20 prepared as described above. In order to produce this duplicate mold, a so-called metal plating method can be adopted. More specifically, as shown in FIG. 2A, first, a thin film 21 made of a metal material such as aluminum, gold, silver, or an alloy containing these metals is formed on the image pattern surface of the relief image duplication master 20. Is formed by a method such as vacuum evaporation, sputtering, or ion plating. The thickness of the metal thin film 21 is 100 angstroms or more.
Preferably, it is 10,000 Angstroms.

Then, as shown in FIG. 2B, a metal plating 22 such as nickel plating is formed on the metal thin film 21 by using a metal thin film 21 as an electrode in a conventional manner. Next, FIG.
As shown in (c), the metal plating layer 22 is
At the same time, it is peeled off from the master 20.

Thereafter, as shown in FIG. 2D, the duplicated mold (22) is obtained by removing the metal thin film 21 from the metal plating layer 22 by an ordinary method. Needless to say, the replica mold can also be made of resin. That is, a sheet or plate made of a thermoplastic resin is brought into close contact with the relief surface of the duplication master, and the relief pattern of the duplication master is transferred to the sheet or plate by heating and pressing.

FIG. 1 shows the duplication mold 22 thus produced.
As shown in (e), an image forming material 2 such as a sheet or a film made of a thermoplastic resin or a thermosetting resin.
The relief pattern 24 is duplicated on the image forming material 23 by heating and pressurizing (embossing) by bringing the 3 into close contact (FIG. 1F).

[0024]

【Example】

Example 1 <Preparation of Relief Pattern Forming Die> A photoresist (MICROPOSIT14 manufactured by Shipley Co., Ltd.) was applied on a support made of a glass plate having a thickness of 3 mm by spin coating.
00) is formed to a thickness of about 1.5 μm, and the area is 9 cm (square) by two-beam interference method using an argon laser (wavelength 457.9 nm, intensity 50 mJ / cm ² ).
An interference fringe having a spatial frequency of 1300 lines / mm was exposed for about 1 minute. Thereafter, a grating pattern was formed on the photoresist surface by alkali development to obtain a relief original plate. Then, a gold thin film having a thickness of about 200 angstroms is formed on the entire photoresist surface of the relief original plate by a vacuum evaporation method.
Nickel plating of 50 μm was applied. Thereafter, the nickel plating layer was peeled off from the relief original plate by an ordinary method, and the gold thin film and the photoresist adhered to the nickel plating layer were removed to obtain a mold for forming a relief pattern.

<Preparation of Relief Image Duplicate Master> Thickness 4
On a 00 μm polymethyl methacrylate (PMMA) sheet, 2 parts by weight of a saturated copolymerized polyester resin (Elitel UE-3201 manufactured by Unitika), 4.5 parts by weight of an acrylic resin (Dianal BR-77 manufactured by Mitsubishi Rayon Co., Ltd.), pentane A photocurable thermoplastic resin composition comprising 3 parts by weight of erythritol hexaacrylate, 0.5 part by weight of tris (acryloxyethyl) isocyanurate, and a photopolymerization initiator (Irgacure 184 manufactured by Ciba Geigy) is 15 parts by weight of 2-butanone. And a solution dissolved in 10 parts by weight of toluene was applied by wire bar coating so that the thickness of the resin composition layer after drying was about 5 μm. Drying was performed at 80 ° C. for 20 minutes.

The relief pattern surface of the mold for forming a relief pattern is brought into close contact with the surface of the resin composition layer,
A flat pressure press treatment was performed at a pressure of 10 kg / cm ² and a temperature of 80 ° C. for 15 seconds. Next, the mixture was rapidly cooled to room temperature with cooling water while maintaining the pressure, and then the mold was removed to transfer a uniform relief pattern of the mold to the surface of the resin composition layer (emboss molding).

Next, a gray scale having four levels of density gradation is brought into close contact with the relief pattern surface of the resin composition layer, and the entire surface is irradiated with ultraviolet light having a total exposure amount of 1200 mJ / cm ² , thereby obtaining a gray scale. A region having a different degree of curing was formed in accordance with the intensity of ultraviolet light transmitted through. In addition,
Exposure amounts of ultraviolet light transmitted through the four gradation gray scale are 155, 470, 736, and 1140 mJ / cm, respectively.
^{Was 2} .

After removing the gray scale, the structure irradiated with ultraviolet light was allowed to stand on a hot plate preheated to 110 ° C. for 5 minutes, and the degree of softening deformation of the surface of the resin composition layer was visually observed. did. As a result, the relief pattern in the region where the exposure amount was 155 mJ / cm ² completely disappeared and appeared to be flattened.
On the other hand, it was confirmed that the relief pattern in the region where the exposure amount was 1140 mJ / cm ² was completely maintained as it was.

After the heat deformation treatment, the entire surface of the resin composition layer was exposed to ultraviolet light to completely cure the resin composition layer and fix the heat deformation pattern. In order to quantitatively evaluate the visual observation result, the diffraction efficiency of the grating relief pattern after the embossing and fixing in each exposure amount region is calculated by the following formula: Diffraction efficiency (%) = (R ₁ / R ₀ ) × 100 (where R ₁ is the first-order diffracted light intensity, and R ₀ is the zero-order diffracted light intensity (normal reflected light component)). A helium-neon laser (wavelength: 633 nm) was used as a light source, and the light intensity was measured as an electromotive force generated by a photodiode. The diffraction efficiency of the grating relief of the mold was 9.2%. The results are shown in Table 1 below.

[0030]

[Table 1]

As can be seen from the results, the region where the exposure amount of the ultraviolet light was 155 mJ / cm ² was 1140 mJ / cm ^2.
/ Cm ² , it was possible to obtain a contrast with a diffraction efficiency close to 100%. Further, the contrast of the thermal deformation pattern between the respective regions was clear.

<Preparation of Duplicate Mold> A gold thin film having a thickness of about 200 angstroms was formed on the entire relief image surface of the relief image duplicating master obtained by performing the above fixing process by a vacuum evaporation method, and this was used as an electrode. About 250μ thick
m of nickel plating. Then, according to the usual method,
Peeling off the nickel plating layer, removing the gold thin film and the photoresist attached to the nickel plating layer,
A duplicate was obtained.

<Replication> Thickness of 25 μm after corona discharge treatment
A solution prepared by dissolving 15 parts by weight of an acrylic copolymer resin (Dianal BR-101 manufactured by Mitsubishi Rayon Co., Ltd.) in 40 parts by weight of isopropanol and 45 parts by weight of 2-butanone was applied onto a base material made of polyester by a roll coater. After drying, a thermoplastic resin layer having a thickness of 3 μm was formed.
Then, the relief pattern surface of the above-mentioned duplication type was brought into close contact with the surface of the thermoplastic resin layer at a pressure of 6 kg / cm and a temperature of 80 ° C., and continuous duplication of a relief image was performed at a speed of about 6 m / min by a roll embossing method. . As a result, a large number of duplicate relief products having excellent design properties were obtained.

Example 2 The same operation as in Example 1 was performed, except that a photographic film of a black-and-white positive image in which a human face was photographed was used instead of the gray scale. As a result, a relief image in which the diffraction light contrast of the grating relief was clear and bright was reproduced.

[0035]

As described above, according to the present invention, the formation of a desired relief image can be achieved by exposing the photocurable thermoplastic resin composition to a dose corresponding to the gradation of the image, and then applying heat to the photocurable thermoplastic resin composition. For example, when a relief-type hologram image is duplicated, it is not necessary to manufacture a hologram master that goes through a complicated process that requires a long time for each different image.
If one is produced, many kinds of relief images can be efficiently duplicated using this.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a process until a relief image duplication master is produced in a relief image duplication method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a process until a relief image is duplicated using a relief image duplication master produced by the process shown in FIG. 1 in the relief image duplication method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Support body 12 ... Photocurable thermoplastic resin composition layer 13 ... Relief pattern 14 ... Relief pattern forming die 15 ... Mask 16, 19 ... Light 20 ... Relief image duplication original plate 21 ... Electrode layer 22 ... Metal plating Layer 23: Image forming material

Claims (2)

[Claims] 1. A photocurable thermoplastic resin composition layer having an uneven relief pattern on the surface and being in a solid state at room temperature is formed on a support, and a desired layer is formed on the thermoplastic resin composition layer. By irradiating light of an irradiation amount corresponding to the gradation of an image, regions having different photocuring degrees are formed in accordance with the irradiation amount of the light, and a thermoplastic resin composition in which the regions having different photocuring degrees are formed. By heating the material layer at a certain temperature, the regions having different photocuring degrees are thermally deformed in accordance with the photocuring degrees, and the heat-deformed thermoplastic resin composition layer is irradiated with light to form a heat deformation pattern. Preparing a relief image duplication master by fixing, a step of producing a duplication mold from the relief image duplication master, and pressing the image forming material on the relief image pattern surface of the duplication mold under heating. The coat The method of duplicating a relief image, characterized in that it comprises the step of replicating the relief image on the image forming member. 2. The method according to claim 1, wherein the light irradiation is performed through a mask having regions having different light transmittances corresponding to a desired image gradation.